For more than 20 years, α1proteinase inhibitor (α1PI or α1antitrypsin) therapy has been the standard treatment for people with insufficient α1PI blood levels. This disorder, also known as α1antitrypsin deficiency, was previously thought to be caused only as an inherited trait due to the gene PIzz. Recent evidence shows that it can also be an acquired disease. Specifically, individuals with HIV-1 disease have been found to have severely low α1PI blood levels (Bristow et al., 2001; Bristow et al., 2010; Bristow et al., 2012). Many people with the inherited version of α1PI deficiency eventually develop emphysema, and among individuals with HIV-1 disease, 90% have acquired α1PI deficiency. Whether they go on to develop emphysema is still unresolved.